1. Field of the Invention
The instant disclosure relates to an antenna; in particular, to a tunable long term evolution antenna.
2. Description of Related Art
The mobile communication devices such as smart phones or tablet PCs have been common in daily life of people. Especially, the third-generation (3G) mobile communication system has been gradually replaced by the fourth-generation (4G) mobile communication system. The insufficient data transfer rate of the 3G mobile communication system could be overcome by the 4G mobile communication system, wherein the long term evolution (LTE) technology is an important standard of the 4G mobile communication system, and most telecommunications providers of many countries are planning to utilize the LTE technology for the 4G mobile communication system.
As for the mobile communication device of the terminal of the users, in order to make use of many bands in the mobile communication system, the manufacturers or research and development engineers of the antenna may apply a variety of designs for the antenna in the mobile communication device to meet a plurality of communication specifications. However, the antenna should be designed to comply with the specifications while applying to the 3G mobile communication system and the specifications of the 4G mobile communication system at the same time, thus it may cause increasing the complexity of antenna design.